For instance, a chassis dynamometer for testing a complete vehicle as Japanese Unexamined Patent Application Publication No. 2011-149921 describes and an engine dynamometer for inspecting only an engine as Japanese Unexamined Patent Application Publication No. 2013-134151 describes are known as conventional test benches of vehicles.
In the chassis dynamometer, the complete vehicle driven by an automatic driving robot (automatic actuator) is placed on rollers, and a mechanical running test is conducted in a predetermined running pattern that simulates actual running. The chassis dynamometer measures the running performance of the vehicle as well as mileage, exhaust gas components, and more. Furthermore, an exhaust gas measuring apparatus or other apparatuses provided in a test bench can be operated in agreement with the chassis dynamometer.
Meanwhile, the engine dynamometer tests only an engine on which a simulated load is placed. In addition to measuring the output performance of the engine, the engine dynamometer measures mileage, exhaust gas components, and more.
In the development and production of vehicles, an engine dynamometer testing device tests an engine, and a chassis dynamometer testing device tests a complete vehicle. Ideally, the results of these two types of tests should be identical, though they frequently differ due to the influence of various factors such as an unexpected overload on the engine. Consequently, following the testing, adjustments are made to the engine, and further repeated testing may be required.
The process of development described above, which involves repeated testing and adjustments, can hinder the speedy development of the engine and its synchronized operation with various other parts and components of the vehicle, such as a transmission and a power train.